<!DOCTYPE html>
<html lang="en">
<body>
	<input type="hidden" />
	<script
		src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>
	<script>
		(function($) {
			// Alerts "true" 
			alert($('input').is(':hidden'));
			// Or, added to wrapper set if hidden. Alerts "1" 
			alert($('input:hidden').length);
		})(jQuery);
	</script>
</body>
</html>